This is an automated cherry-pick of pingcap#49844

Signed-off-by: ti-chi-bot <ti-community-prow-bot@tidb.io>
ti-chi-bot · Dec 28, 2023 · ae3016d · ae3016d
1 parent 20c3e7d
commit ae3016d
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Showing 4 changed files with 861 additions and 2 deletions.
diff --git a/pkg/planner/core/plan.go b/pkg/planner/core/plan.go
@@ -85,7 +85,9 @@ func enforceProperty(p *property.PhysicalProperty, tsk task, ctx sessionctx.Cont
 		}
 		tsk = mpp.enforceExchanger(p)
 	}
-	if p.IsSortItemEmpty() || tsk.plan() == nil {
+	// when task is double cop task warping a index merge reader, tsk.plan() may be nil when indexPlanFinished is marked
+	// as false, while the real plan is in idxMergePartPlans. tsk.plan()==nil is not right here.
+	if p.IsSortItemEmpty() || tsk.invalid() {
 		return tsk
 	}
 	if p.TaskTp != property.MppTaskType {

diff --git a/pkg/planner/core/task.go b/pkg/planner/core/task.go
@@ -101,7 +101,7 @@ type copTask struct {
 }
 
 func (t *copTask) invalid() bool {
-	return t.tablePlan == nil && t.indexPlan == nil
+	return t.tablePlan == nil && t.indexPlan == nil && len(t.idxMergePartPlans) == 0
 }
 
 func (t *rootTask) invalid() bool {
@@ -120,6 +120,8 @@ func (t *copTask) copy() task {
 	return &nt
 }
 
+// copTask plan should be careful with indexMergeReader, whose real plan is stored in
+// idxMergePartPlans, when its indexPlanFinished is marked with false.
 func (t *copTask) plan() PhysicalPlan {
 	if t.indexPlanFinished {
 		return t.tablePlan